In a typical modern recreational watercraft all informational gauges, including the fuel level gauge, that provide operational and status information to the operator are mounted on a dashboard at the helm. These gauges are useful when operating the watercraft, but are not supplied with power and therefore are not usable when the vessel is in storage, on the trailer, at a fuel pump or at a dock. To determine the fuel level in the vessel, for example, the operator must board the watercraft and activate the fuel gauge by turning on the battery supply.
During a refueling operation the watercraft engine is typically off. Without power, the informational gauges cannot provide status or operational information. Additionally, without visual access to the dash-mounted fuel gauge, the operator cannot determine the fuel level during refueling, resulting in a best guess as to the tank fuel level. Unless the operator climbs aboard the vessel while refueling and activates the fuel level gauge, a significant inconvenience, he is prone to over fill or under fill the fuel tank. In the latter case, the operator may have to return to the dock to refuel earlier than desired. In the former case, the resulting fuel spill wastes fuel and causes environmental damage. Filling the tank to capacity may also be undesirable as the fuel may become stale in the tank due to infrequent use of the vessel.
In addition to the inconveniences associated with using the analog helm-mounted fuel gauge during refueling, the indicated fuel level reading is known to be inaccurate, perhaps as much as 15% inaccurate, due to variations in the battery voltage and inaccuracies associated with the fuel gauge calibration. That is, the gauge is calibrated using a certain fuel tank shape, but the operator's vessel tank shape is likely different therefrom, resulting in inaccurate readings as to the quantity of fuel remaining in the tank.